Vibration Analysis And Birdge Damage Detection Based On Bridge-vehicle Coupled System

In recent years, China's bridge construction has made great achievements, the bridge structure is also goes to the soft,large-scale,functional complexity and other directions,both in size and number of bridges has reached the world leading level.While the accompanying problem such as maintenance and management is occurred due to the environmental changes,traffic load, fatigue damage and other impacts during service. Therefore, it's significant to built a bridge health monitoring system to insure the security and durability of bridge. In this paper,the bridge damage identification is main purpose, the vibration response of vehicle-bridge coupling damage model was analyzed, the damage site and degree of the bridge structure was successfully identified by sensitivity damage identification algorithm, combined with multi-body dynamics and finite element analysis software to build a more complex bridge-vehicle coupling modal including concrete box girder and high speed train. The dynamic response of the box girder under damage is discussed, and the damage index of the bridge are established by combining the system chaos theory, the research results have certain engineering value, the main contents include:(1) A 10 degrees of freedom vehicle model and the 16 finite elements of simple supported beam model were established based on bridge-vehicle coupling theory.The displacement,velocity and acceleration response of the vehicle body and bridge were computed during crossing the bridge,then the different damage conditions were simulated to analysis the regulation between response and damage.Lastly,the factor such as vehicle speed, road roughness, bridge span were considered.(2) Using the established mathematical model of vehicle bridge coupling to introduce the sensitivity damage identification algorithm.Firstly,computing the response of the vehicle body and bridge as source data,then sensitivity equation were given to recognize the damage,the parameter such as noise effects and vehicle speeds were discussed to evaluate the effect of damage identification accuracy.(3) In order to simulate the true state of vehicle bridge coupling modal,using the multi-body dynamics and FEM software based on high speed train named TGV and concrete box girder model,simulating various bridge damage conditions to analysis the dynamic response,putting forward a new damage index named lyapunov exponent,it turns out that this index could represent the changes of damage,it's usefull for bridge health monitoring.